The main methods for determining free amino acids include pre column derived reverse phase chromatography, post column derived ion exchange chromatography, ion chromatography integrated pulse amperometry, liquid chromatography evaporative emission detection, liquid chromatography-mass spectrometry, etc. Among them, pre column derived reverse phase chromatography and post column derived ion exchange chromatography are commonly used methods for amino acid determination. Due to the high cost of purchasing amino acid analyzers for detection in post column derivatization ion exchange chromatography, manual offline derivatization before separation and detection using liquid chromatography ultraviolet detection can be preferred in most cases.

Shanghai Tongwei Analysis Technology Co., Ltd. adopts Tongwei EasySep to address the difficulty of amino acid separation and detection ® A series of liquid chromatography systems, combined with a UNISIL AA (4.6 mm × 250 mm, 5 μ m) amino acid analysis column, were used to separate and detect 17 amino acids using pre column PITC derived amino acid method.